255
FNCA52 TJSJ 200730
FWFSJU
FIRE WEATHER PLANNING FORECAST FOR PUERTO RICO
NATIONAL WEATHER SERVICE SAN JUAN PR
330 AM AST WED MAY 20 2026
DISCUSSION
INCREASING MOISTURE TODAY COULD PREVENT RH VALUES FROM DECREASING
BELOW THRESHOLD VALUES FOR PROLONGED PERIODS; HOWEVER, RAINFALL
SHOULD AGAIN REMAIN LIMITED ACROSS THE SOUTHERN PLAINS, ALLOWING
RELATIVE HUMIDITY TO DROP TO CRITICAL FIRE WEATHER THRESHOLDS IN
THE REGION. ADDITIONALLY, SUSTAINED WINDS OF 15 TO AROUND 20 MPH,
WITH HIGHER GUSTS, COMBINED WITH ELEVATED KBDI VALUES, WILL FAVOR
THE RAPID SPREAD OF WILDFIRES ACROSS THE SOUTHERN COASTAL PLAINS.
THE LOW 7-DAY PERCENT OF NORMAL RAINFALL WILL ALSO PERSIST ACROSS
THE SOUTHEASTERN COASTAL PLAINS. FIRE MANAGEMENT PARTNERS ARE
ONCE AGAIN URGED TO REMAIN VIGILANT.
PRZ014-202000-
SOUTHEAST COASTAL PLAINS-
330 AM AST WED MAY 20 2026
TODAY TONIGHT THU
CLOUD COVER PCLDY PCLDY PCLDY
PRECIP TYPE SHOWERS SHOWERS SHOWERS
CHANCE PRECIP (%) 40 30 40
TEMP (24H TREND) 89 (+1) 72 (-2) 90
RH % (24H TREND) 48 (-5) 86 (+2) 49
WIND 20FT/EARLY(MPH) E 17 E 14 E 17
WIND 20FT/LATE(MPH) E 18 E 12 SE 18
MIXING HGT(FT-AGL/MSL)5150 5520
TRANSPORT WND (MPH) E 20 E 17
VENT RATE (KT-FT) 87550 82800
DISPERSION 5 5
DSI 6 5 6
RH RECOVERY EXCELLENT
REMARKS...NONE.
PRZ015-202000-
SOUTHERN HILLS-
330 AM AST WED MAY 20 2026
TODAY TONIGHT THU
CLOUD COVER PCLDY MCLEAR PCLDY
PRECIP TYPE SHOWERS SHOWERS SHOWERS
CHANCE PRECIP (%) 40 20 30
TEMP (24H TREND) 86 (+3) 68 (-3) 87
RH % (24H TREND) 60 (-3) 93 (+2) 56
WIND 20FT/EARLY(MPH) E 14 E 13 E 13
WIND 20FT/LATE(MPH) E 16 E 13 SE 13
MIXING HGT(FT-AGL/MSL)5960 6350
TRANSPORT WND (MPH) E 20 E 15
VENT RATE (KT-FT) 101320 82550
DISPERSION 5 5
DSI 6 4 6
RH RECOVERY EXCELLENT
REMARKS...NONE.
PRZ016-202000-
NORTH COASTAL PLAINS-
330 AM AST WED MAY 20 2026
TODAY TONIGHT THU
CLOUD COVER PCLDY PCLDY PCLDY
PRECIP TYPE SHOWERS SHOWERS TSTMS
CHANCE PRECIP (%) 40 30 40
TEMP (24H TREND) 89 (+1) 71 (-2) 90
RH % (24H TREND) 57 (-4) 94 (+2) 55
WIND 20FT/EARLY(MPH) E 17 E 17 E 14
WIND 20FT/LATE(MPH) E 20 E 12 E 21
MIXING HGT(FT-AGL/MSL)5660 6130
TRANSPORT WND (MPH) E 20 E 17
VENT RATE (KT-FT) 96220 91950
DISPERSION 5 5
DSI 6 6 6
RH RECOVERY EXCELLENT
REMARKS...NONE.
PRZ017-202000-
NORTHERN HILLS-
330 AM AST WED MAY 20 2026
TODAY TONIGHT THU
CLOUD COVER PCLDY MCLEAR PCLDY
PRECIP TYPE TSTMS SHOWERS TSTMS
CHANCE PRECIP (%) 50 10 60
TEMP (24H TREND) 88 (+1) 69 (-2) 88
RH % (24H TREND) 59 (0) 94 (+1) 55
WIND 20FT/EARLY(MPH) E 16 E 14 E 13
WIND 20FT/LATE(MPH) E 19 E 10 E 18
MIXING HGT(FT-AGL/MSL)6660 7200
TRANSPORT WND (MPH) E 16 E 13
VENT RATE (KT-FT) 93240 79200
DISPERSION 5 5
DSI 6 4 6
RH RECOVERY EXCELLENT
REMARKS...NONE.
PRZ018-202000-
WEST COAST-
330 AM AST WED MAY 20 2026
TODAY TONIGHT THU
CLOUD COVER PCLDY MCLEAR PCLDY
PRECIP TYPE TSTMS SHOWERS TSTMS
CHANCE PRECIP (%) 40 10 40
TEMP (24H TREND) 90 (0) 72 (-1) 91
RH % (24H TREND) 59 (+1) 91 (+2) 55
WIND 20FT/EARLY(MPH) E 16 E 17 E 14
WIND 20FT/LATE(MPH) E 17 E 11 E 14
MIXING HGT(FT-AGL/MSL)5160 5170
TRANSPORT WND (MPH) E 14 E 10
VENT RATE (KT-FT) 61920 46530
DISPERSION 5 5
DSI 6 5 6
RH RECOVERY EXCELLENT
REMARKS...NONE.
PRZ019-202000-
EASTERN INTERIOR-
330 AM AST WED MAY 20 2026
TODAY TONIGHT THU
CLOUD COVER PCLDY PCLDY PCLDY
PRECIP TYPE SHOWERS SHOWERS SHOWERS
CHANCE PRECIP (%) 40 30 40
TEMP (24H TREND) 86 (+1) 69 (-3) 87
RH % (24H TREND) 61 (-2) 94 (0) 57
WIND 20FT/EARLY(MPH) E 17 E 14 E 14
WIND 20FT/LATE(MPH) E 16 E 14 E 14
MIXING HGT(FT-AGL/MSL)5980 6870
TRANSPORT WND (MPH) E 20 SE 16
VENT RATE (KT-FT) 101660 96180
DISPERSION 5 5
DSI 6 4 6
RH RECOVERY EXCELLENT
REMARKS...NONE.
PRZ022-202000-
LUQUILLO MOUNTAIN RANGE-
330 AM AST WED MAY 20 2026
TODAY TONIGHT THU
CLOUD COVER PCLDY PCLDY PCLDY
PRECIP TYPE SHOWERS SHOWERS SHOWERS
CHANCE PRECIP (%) 50 40 50
TEMP (24H TREND) 82 (+3) 68 (-2) 82
RH % (24H TREND) 66 (-6) 97 (0) 64
WIND 20FT/EARLY(MPH) E 14 E 12 E 13
WIND 20FT/LATE(MPH) E 14 E 11 E 13
MIXING HGT(FT-AGL/MSL)4710 4450
TRANSPORT WND (MPH) E 21 E 20
VENT RATE (KT-FT) 84780 75650
DISPERSION 5 5
DSI 6 5 6
RH RECOVERY EXCELLENT
REMARKS...NONE.
PRZ023-202000-
CENTRAL MOUNTAIN RANGE-
330 AM AST WED MAY 20 2026
TODAY TONIGHT THU
CLOUD COVER PCLDY MCLEAR PCLDY
PRECIP TYPE TSTMS SHOWERS TSTMS
CHANCE PRECIP (%) 50 0 50
TEMP (24H TREND) 85 (+3) 66 (-3) 86
RH % (24H TREND) 62 (-2) 95 (+2) 57
WIND 20FT/EARLY(MPH) E 11 E 10 E 10
WIND 20FT/LATE(MPH) E 12 E 9 SE 11
MIXING HGT(FT-AGL/MSL)7240 7730
TRANSPORT WND (MPH) E 15 SE 8
VENT RATE (KT-FT) 94120 54110
DISPERSION 5 5
DSI 6 2 6
RH RECOVERY EXCELLENT
REMARKS...NONE.
PRZ024-202000-
CAYEY MOUNTAIN RANGE-
330 AM AST WED MAY 20 2026
TODAY TONIGHT THU
CLOUD COVER PCLDY PCLDY PCLDY
PRECIP TYPE SHOWERS SHOWERS SHOWERS
CHANCE PRECIP (%) 50 30 50
TEMP (24H TREND) 82 (+2) 68 (-2) 82
RH % (24H TREND) 68 (0) 96 (-2) 65
WIND 20FT/EARLY(MPH) E 13 E 11 E 12
WIND 20FT/LATE(MPH) E 13 E 11 E 12
MIXING HGT(FT-AGL/MSL)5110 5560
TRANSPORT WND (MPH) E 20 E 17
VENT RATE (KT-FT) 86870 83400
DISPERSION 5 5
DSI 6 5 6
RH RECOVERY EXCELLENT
REMARKS...NONE.
PRZ025-202000-
VIEQUES-
330 AM AST WED MAY 20 2026
TODAY TONIGHT THU
CLOUD COVER PCLDY PCLDY PCLDY
PRECIP TYPE SHOWERS SHOWERS SHOWERS
CHANCE PRECIP (%) 40 20 30
TEMP (24H TREND) 86 (0) 74 (-2) 87
RH % (24H TREND) 60 (-3) 87 (-1) 60
WIND 20FT/EARLY(MPH) E 19 E 18 E 17
WIND 20FT/LATE(MPH) E 19 E 18 E 17
MIXING HGT(FT-AGL/MSL)3980 3820
TRANSPORT WND (MPH) E 21 E 22
VENT RATE (KT-FT) 71640 72580
DISPERSION 5 5
DSI 6 6 6
RH RECOVERY EXCELLENT
REMARKS...NONE.
PRZ026-202000-
CULEBRA-
330 AM AST WED MAY 20 2026
TODAY TONIGHT THU
CLOUD COVER PCLDY PCLDY PCLDY
PRECIP TYPE SHOWERS SHOWERS SHOWERS
CHANCE PRECIP (%) 40 30 50
TEMP (24H TREND) 89 (+2) 75 (-3) 89
RH % (24H TREND) 57 (-7) 86 (0) 58
WIND 20FT/EARLY(MPH) E 19 E 18 E 17
WIND 20FT/LATE(MPH) E 19 E 18 E 17
MIXING HGT(FT-AGL/MSL)4080 3930
TRANSPORT WND (MPH) E 24 E 22
VENT RATE (KT-FT) 85680 74670
DISPERSION 5 5
DSI 6 6 6
RH RECOVERY EXCELLENT
REMARKS...NONE.
PRZ027-202000-
SOUTHWEST COASTAL PLAINS AND MONA ISLAND-
330 AM AST WED MAY 20 2026
TODAY TONIGHT THU
CLOUD COVER PCLDY MCLEAR PCLDY
PRECIP TYPE SHOWERS SHOWERS SHOWERS
CHANCE PRECIP (%) 50 20 30
TEMP (24H TREND) 91 (+2) 73 (-2) 91
RH % (24H TREND) 50 (-3) 83 (+2) 49
WIND 20FT/EARLY(MPH) E 21 E 23 E 20
WIND 20FT/LATE(MPH) SE 23 G30 E 16 SE 20
MIXING HGT(FT-AGL/MSL)5290 5360
TRANSPORT WND (MPH) E 23 E 20
VENT RATE (KT-FT) 105800 91120
DISPERSION 5 5
DSI 6 6 6
RH RECOVERY EXCELLENT
REMARKS...NONE.
VIZ001-202000-
SAINT THOMAS AND SAINT JOHN-
330 AM AST WED MAY 20 2026
TODAY TONIGHT THU
CLOUD COVER PCLDY PCLDY PCLDY
PRECIP TYPE SHOWERS SHOWERS SHOWERS
CHANCE PRECIP (%) 40 30 40
TEMP (24H TREND) 86 (+1) 75 (-2) 86
RH % (24H TREND) 60 (-6) 89 (+2) 60
WIND 20FT/EARLY(MPH) E 19 E 18 E 18
WIND 20FT/LATE(MPH) E 19 E 18 E 18
MIXING HGT(FT-AGL/MSL)4120 3610
TRANSPORT WND (MPH) E 25 E 21
VENT RATE (KT-FT) 90640 64980
DISPERSION 5 5
DSI 6 6 6
RH RECOVERY EXCELLENT
REMARKS...NONE.
VIZ002-202000-
ST CROIX-
330 AM AST WED MAY 20 2026
TODAY TONIGHT THU
CLOUD COVER PCLDY MCLEAR PCLDY
PRECIP TYPE SHOWERS SHOWERS SHOWERS
CHANCE PRECIP (%) 40 10 30
TEMP (24H TREND) 87 (+1) 74 (-2) 87
RH % (24H TREND) 61 (-4) 85 (-3) 62
WIND 20FT/EARLY(MPH) E 19 E 18 E 17
WIND 20FT/LATE(MPH) E 17 E 17 E 17
MIXING HGT(FT-AGL/MSL)4750 5010
TRANSPORT WND (MPH) E 23 E 23
VENT RATE (KT-FT) 95000 100200
DISPERSION 5 5
DSI 6 6 6
RH RECOVERY EXCELLENT
REMARKS...NONE.
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